π¦ SAP MM (Materials Management) interview guide
Procure-to-Pay from requirement to vendor payment, plus inventory, valuation, account determination and the S/4HANA changes interviewers test today.
Procure-to-PayPurchasingInventoryValuationMIRO
SAP Materials Management (MM) handles everything a company buys and stores: purchasing, inventory management, valuation and invoice verification. Its core process is Procure-to-Pay (P2P). MM integrates tightly with FI, CO, SD, PP, PM and PS, so strong MM consultants are always in demand.
π Jump to the scored MM test
What is SAP MM?
Key MM areas:
- Purchasing: purchase requisitions, RFQs and quotations, purchase orders, contracts, scheduling agreements and source determination.
- Inventory management: goods receipts, goods issues, transfer postings, reservations and physical inventory, all controlled by movement types.
- Valuation & account determination: standard (S) or moving average (V) price, valuation classes and automatic G/L postings (OBYC).
- Logistics Invoice Verification: 3-way match of PO, goods receipt and invoice (MIRO).
- MRP / consumption-based planning: reorder point and forecast-based planning that generate requirements.
Special procurement types you must know: subcontracting, consignment, stock transport orders, third-party and pipeline.
End-to-end process: Procure-to-Pay (P2P)
“Explain P2P” is the classic MM opener. Mention the document, the T-code and the accounting entry at each step.
- Determine requirement
MD01N / ME51N
MRP or a user creates a purchase requisition for materials or services, with account assignment if consumed directly (K, F, P, A). - Approve requisition
ME54N Β· Release / workflow
Release strategy (classification-based) or flexible workflow in S/4HANA approves the PR by value, plant or material group. - Find source of supply
Info record Β· Source list
Source determination uses purchasing info records, source lists, quota arrangements, contracts and scheduling agreements. - RFQ & quotation
ME41 / ME47 / ME49
Request quotations from suppliers, enter the prices and compare them (price comparison) to select the best supplier. - Create purchase order
ME21N
The PO is the legal document with supplier, prices, delivery dates, terms and account assignment. Pricing comes from conditions. - Approve & send PO
ME29N Β· Output
PO release strategy or workflow, then output to the supplier via print, email, EDI or SAP Ariba. - Supplier confirmation
Order ack Β· ASN
Order acknowledgements and inbound deliveries (ASN) update expected dates and quantities. - Goods receipt
MIGO Β· Mvt 101
GR increases stock and posts Inventory Dr / GR-IR Cr. Quality inspection may be triggered through QM. - Manage inventory
Mvt 311 / 201 / MI01
Transfer postings, issues to cost centres or orders, reservations and physical inventory counts keep stock accurate. - Invoice verification
MIRO Β· 3-way match
The invoice is matched with the PO and GR. It posts GR-IR Dr / Vendor Cr, and variances post to price difference or are blocked. - Vendor payment
F110 Β· Payment run
The automatic payment program pays due invoices according to payment terms and clears the open items. - Clear & analyse
MR11 Β· Spend analytics
Maintain the GR/IR clearing account and analyse spend, supplier performance and purchasing KPIs.
Organizational structure & master data
Organizational structure
Client & company code
Client is the top level. The company code is the independent legal entity.
Plant & storage location
Plants are assigned to one company code. Storage locations sit below plants.
Purchasing organisation
Centralised (assigned to many company codes / plants), company-code specific or plant specific. A reference purchasing org allows contracts to be shared.
Purchasing group
Not assigned to any org unit. It represents buyers and is used for reporting and release.
Valuation level
Set at plant or company code level and cannot easily be changed later. Plant level is mandatory for PP and recommended.
Master data
Material master (MM01)
- Views: Basic, Purchasing, MRP, Accounting, Costing, Plant/Storage
- Material type controls views, number range and valuation
- Price control S (standard) or V (moving average)
Business Partner supplier
Created through BP with supplier roles (FLVN00 for FI, FLVN01 for purchasing) and synchronised by CVI.
Purchasing info record (ME11)
Supplier-material relationship with prices, conditions, planned delivery time and tolerances.
Source list (ME01)
Allowed or fixed suppliers for a material and plant over a validity period.
Outline agreements
- Value or quantity contracts (ME31K)
- Scheduling agreements (ME31L)
Quota arrangement (MEQ1)
Splits requirements between suppliers by percentage.
Key T-codes & Fiori apps
Interviewers often ask you to name the transaction or app for a step. You do not need to memorise hundreds, but you should know these confidently.
| T-code / App | What it does |
|---|---|
| ME51N / ME52N / ME53N | Create / change / display purchase requisition |
| ME54N / ME55 | Release PR individually / collectively |
| ME21N / ME22N / ME23N | Create / change / display purchase order |
| ME29N / ME28 | Release PO individually / collectively |
| ME41 / ME47 / ME49 | Create RFQ / maintain quotation / price comparison |
| ME31K / ME31L | Create contract / scheduling agreement |
| ME11 / ME01 / MEQ1 | Info record / source list / quota arrangement |
| MIGO | Goods movements (GR, GI, transfer posting) |
| MIRO / MIR4 / MRBR | Enter invoice / display / release blocked invoices |
| MMBE / MB52 | Stock overview / warehouse stock |
| MI01 / MI04 / MI07 | Create physical inventory doc / enter count / post differences |
| OBYC / OMWB | Automatic account determination |
| MD01N | MRP Live (S/4HANA) |
| Fiori: Manage Purchase Requisitions, Manage Purchase Orders, Monitor Material Coverage | Modern procurement and inventory apps |
What changed in S/4HANA
- Business Partner replaces separate vendor master transactions (XK01, MK01).
- MATDOC becomes the single table for material documents, replacing MKPF/MSEG and the stock aggregate tables. Stock is computed on the fly, which allows much higher throughput.
- Material Ledger is mandatory for inventory valuation in parallel currencies. Actual costing stays optional.
- MRP Live (MD01N) runs MRP in HANA, with Fiori apps for material coverage and predictive MRP.
- Flexible workflow for PR, PO and other documents is available as a modern alternative to classification-based release strategies.
- The material number is extended to 40 characters, and Central Procurement and SAP Ariba integration support hub procurement scenarios.
- Situation handling and analytics (spend, supplier evaluation) come with embedded CDS views and Fiori.
Integration points
| With | How it integrates |
|---|---|
| FI | GR posts Inventory / GR-IR, MIRO posts GR-IR / Vendor, and F110 pays. Account determination is in OBYC by valuation class and transaction key. |
| CO | Consumption to cost centres, internal orders, WBS or maintenance orders via account assignment categories. Standard cost estimates set the S price. |
| SD | Third-party orders, stock transport orders, availability check, and consignment stock. |
| PP | MRP creates planned orders and PRs. Goods issues to production orders (261) and GR from production (101). |
| QM | Inspection lots at GR, quality info records and supplier evaluation. |
| PM / PS | Spare parts reservations and service procurement for maintenance orders and project activities. |
| WM / EWM | Putaway and picking for goods receipts and issues. |
Interview questions & answers
Tap a question to see a model answer. They are grouped from fundamentals to scenario-based questions that senior panels love.
π’ Fundamentals
Explain the Procure-to-Pay cycle. Beginner
Requirement (PR, manually or from MRP), PR approval, source determination, optional RFQ and quotation, purchase order, PO approval and output, goods receipt (101: Inventory Dr / GR-IR Cr), invoice verification (MIRO: GR-IR Dr / Vendor Cr) and vendor payment (F110: Vendor Dr / Bank Cr).
What is the difference between standard price and moving average price? Beginner
Standard price (S) keeps the price fixed. Differences from PO or invoice prices go to a price difference account. Common for manufactured materials. Moving average price (V) recalculates the average with each receipt. Common for purchased and trading goods.
What are movement types? Give examples. Beginner
Three-digit keys that control a goods movement, its quantity and value update, and the account determination. Examples: 101 GR for PO, 102 GR reversal, 122 return to vendor, 201 GI to cost centre, 261 GI to order, 311 transfer storage location to storage location, 551 scrapping, 561 initial stock entry.
What is a purchasing info record? Beginner
Master data for the supplier-material (or supplier-material group) relationship: price and conditions, planned delivery time, tolerances and the last PO. It can be at purchasing org or plant level and defaults into POs.
What are account assignment categories? Beginner
They define where the cost of a purchase goes when it is consumed directly rather than stocked: K cost centre, F internal order, P project (WBS), A asset, N network, E/M sales order and more.
What is the purpose of the GR/IR account? Beginner
A clearing account that bridges goods receipt and invoice receipt. GR credits it and invoice receipt debits it. Open balances show goods received but not invoiced, or invoiced but not received. MR11 maintains and clears differences.
π‘ Intermediate
Explain automatic account determination in MM. Intermediate
OBYC links transaction keys (BSX inventory, WRX GR/IR, PRD price difference, GBB offsetting entry, KBS account-assigned purchases) with the valuation class (from the material master accounting view), valuation grouping code and account modifier to G/L accounts. The movement type determines which transaction keys apply.
What is a release strategy? Intermediate
Approval control for PRs, POs, contracts and RFQs. Characteristics (value, plant, material group, document type) in a class determine the release strategy. Release groups and codes represent approvers. The document is blocked until all required codes release it. In S/4HANA, flexible workflow is an alternative.
Explain the subcontracting process. Intermediate
A PO with item category L is created for the subcontractor. Components are provided to the vendor (mvt 541, special stock O). The vendor processes them and returns the finished material. GR (101) consumes the components (543) automatically, and the invoice covers the processing charge.
Explain the vendor consignment process. Intermediate
The vendor’s stock is kept in your warehouse (special stock K) without valuation. When you withdraw it for consumption or transfer it to own stock (411 K), the liability arises. Settlement runs with MRKO, which creates the invoice document.
What is a stock transport order (STO)? Intermediate
A PO between plants. Within the same company code it uses document type UB (single or two-step, mvt 641/101 via delivery). Across company codes it uses document type NB with SD billing for intercompany. A delivery (VL10B) and goods issue start the transfer.
How does 3-way matching work in MIRO? Intermediate
The invoice quantity and price are compared with the PO price and the GR quantity (GR-based IV). Tolerance keys (OMR6), such as PP for price and DQ for quantity, decide whether the invoice is blocked for payment. Blocked invoices are released through MRBR.
π΄ Scenario & design
A GR posts to the wrong G/L account. How do you investigate? Scenario
Check the valuation class in the material accounting view, the movement type and its transaction key / account modifier (OMJJ, OMWN), the valuation grouping code of the plant, and the OBYC entries for BSX and GBB. Simulate the posting in MIGO to see the account determination.
The business wants POs above 5 lakh to be approved by the plant head and above 25 lakh by the CFO. How do you design it? Scenario
With classification-based release: characteristics for total value and plant, release codes for buyer, plant head and CFO, and a release strategy with value ranges. Or in S/4HANA, use flexible workflow for purchase orders, with conditions on value and plant and agents determined by role. Include the GR/IR and change management rules (re-approval on value changes).
How would you migrate open POs and stock to S/4HANA? Scenario
Use Migration Cockpit objects for suppliers (BP), materials, info records, source lists, contracts, open POs (with remaining quantities) and stock balances (561 at agreed values). Sequence: org setup, then master data, then open documents and stock at cutover. Reconcile quantities and values with Finance.
Users complain that the MRP run is slow and creating too many requisitions. What do you check? Scenario
Move to MRP Live (MD01N), and review MRP types, lot sizing procedures, safety stock, planning horizon, MRP areas and planned delivery times. Clean up old open requirements and orders. Use Fiori coverage apps to manage exceptions rather than mass PRs.
How do you handle service procurement? Scenario
Use service masters or free-text services with item category D (or lean services in S/4HANA), an account assignment, and a service entry sheet (ML81N or the Fiori app) instead of GR, followed by invoice verification against the accepted services.
What would you propose to integrate SAP Ariba with S/4HANA? Scenario
SAP Ariba Network for PO and invoice collaboration, and Ariba Sourcing and Contracts upstream. Integrate through SAP Integration Suite (managed gateway / cloud integration), with master data sync for suppliers and materials, PO transmission, order confirmations, ASNs and invoices flowing back to MIRO.
What KPIs would you build for a procurement head? Scenario
Spend by category and supplier, PO cycle time, percentage of spend under contract, on-time delivery, invoice first-time-match rate, maverick buying, and GR/IR ageing. All available through embedded analytics and Fiori procurement apps.
Solution architect view
Key MM design decisions:
- Procurement model: centralised, decentralised or hybrid purchasing organisations, plus Central Procurement for multi-system landscapes.
- Valuation: plant-level valuation, price control by material type, material ledger and actual costing decisions with Controlling.
- Approval design: release strategy vs flexible workflow, aligned with the delegation-of-authority matrix.
- Inventory: IM only, WM, or EWM (embedded or decentralised) based on warehouse complexity.
- Supplier collaboration: SAP Ariba, EDI or a supplier portal.
- Planning: MRP Live, MRP areas and replenishment strategies with PP.
- Account determination: valuation classes and OBYC designed with Finance for clean reporting.
Typical deliverables: P2P process design, enterprise structure design, release and workflow matrix, account determination workbook, and migration plan for suppliers, materials, info records, open POs and stock.
Test yourself: scored MM quiz
Interview tips
π‘ How to stand out
- Narrate P2P with T-codes and the accounting entry at GR, invoice and payment.
- Memorise core movement types (101, 122, 201, 261, 311, 541, 561, 601) and OBYC keys (BSX, WRX, PRD, GBB).
- Be ready to explain subcontracting, consignment and STO step by step.
- Mention S/4HANA: MATDOC, BP, MRP Live, flexible workflow and Ariba.
- For senior roles, explain how you designed approvals and valuation with Finance.
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